G. PANAYOTOVA and D. DECHEV
Cotton and Durum Wheat Research Institute, BG-6200 Chirpan, Bulgaria
PANAYOTOVA, G. and D. DECHEV, 2003. Genotype-by-Nitrogen interaction for yield in durum wheat. Bulg. J. Agric. Sci., 9: 173–178
The study was carried out to determine the grain yield stability of six durum wheat genotypes grown at Cotton and Durum Wheat Research Institute, Chirpan during 1994–1997. Nitrogen in rates 0, 3, 6, 9, 12, 15 and 18 kg.da–1 was tested. According to the analysis of variance, genotype – by – year and nitrogen– by – year interaction were significant. For estimation of yield stability a computer program STABLE was used and were determined the parameters of stability: variance (σi2) by Shukla, ecovalence (Wi) by Wricke and Kang's parameter (YSi) for simultaneous evaluation of yield and stability.
The results showed that from the tested genotypes in terms of grain yield, the highest phenotypic stability were possessed by Zagorka, D-5345, and D-5499 and they lower reacted with change of environment. They are more difficult for effective selection and unsuitable for farm production. The Kang's parameters determined as most valuable the genotype Progress, followed by D-5345 and D-482. These genotypes possessed high yield potential and good stability and they can be recommended for different environments. Variety Progress formed a maximum productivity at fertilization of 9 kg N.da–1, while the grain yield of all other genotypes is best when a higher N rate – 12 kg.da–1 was applied. The years appear to be the greatest source of variance of grain yield. Parameters of stability presented as most valuable as referring to yield rate and stability a N rate 9 kg.da–1, regardless of variety and year conditions.